This invention relates to a caliper, i.e. an instrument for measuring the diameter of tree stems. The invention, more precisely, relates to a caliper, which is capable by electronic means to read and preferably to record the diameter of the measured stem.
In the most usual method of measurement in a forest one man measures the diameter of a stem by means of a caliper, whereafter a second man writes down the result. These lists of measurement results are later possibly fed into a computer via punched cards, for example.
There exist also calipers, which by electronic means read the diameter of the measured stem. These calipers, however, have the disadvantages above all of being relatively heavy and large, which is an important disadvantage in view of the fact that the calipers must be carried about all the day, and further of consuming relatively much energy, which implies that either large batteries are to be used, which contributes to an increase in weight, or that the batteries must be exchanged often. These disadvantages are the reason why such calipers are applied to a very limited extent.
The present invention eliminates the aforesaid disadvantages.